The Ins and Outs of In and Out

Sex’s enduring mysteries can be great for pillow talk

The American TV drama Masters Of Sex may never make it to our set-top boxes, but this Mad Men-era series about pioneering sex researchers William Masters (a respected OB and gynaecologist) and Virginia Johnson (his secretary-turned-partner) is certainly worth trawling the Internet for. In the series, Masters proposes a seemingly modest scientific inquiry: “What happens to the body during sex?” In real life, and over more than three decades of highly charged collaboration, the pair gathered data from thousands of “complete cycles of sexual response” – and also experimented on each other. But even with all the research that Masters and Johnson did and inspired, researchers haven’t stopped asking a lot of basic questions about sex. Here’s what science is still wondering.

How can scientists recreate sex in a laboratory? Masters and Johnson conducted research with the help of a motor-powered plexiglass phallus nicknamed Ulysses. Though their gadgets are growing ever more sophisticated, today’s sex scientists are still not sure how their tools affect the act and, therefore, the data. One approach: Have women recline in a La-Z-Boy and watch sexually explicit images with a blood flow-sensing plethysmograph attached to their vaginas. But that’s not something you do every day. Probably.

Why don’t some women orgasm from intercourse? Women faking orgasms was one of Masters’ obsessions. One recent study found that women who report having more orgasms boast a shorter distance between their clitoris and their vagina. But psychological causes are harder to establish: “If you find a woman who’s happily partnered, you can’t randomly assign her to someone else,” says Debby Herbenick, a sexual health educator at the Kinsey Institute.

How can sex scientists parse the distinction between nature and nurture? Modern studies of caged monkeys mating and lab rats’ vaginas have helped inform the animalistic qualities of our own sex lives. But culture isn’t so easily corralled. “When sex becomes a human characteristic, it becomes so much more complicated,” says J Dennis Fortenberry, senior research scientist at Kinsey.

How does external stimulation produce an orgasm? Masters and Johnson outlined an enduring framework for the stages of sex. But scientists are still trying to understand arousal. Some people can think themselves to orgasm; others need zero mental preparation. Herbenick is studying the phenomenon of exercise-induced orgasm: no partner – and, for men, sometimes no erection – required.